Dynamic assessment of cerebral blood flow and intracranial pressure during inversion table tilt using ultrasonography.

CONTEXT

Inversion tables are used as treatment for back pain, but there is a lack of agreement on systemic effects of inversion.

OBJECTIVE

To assess intracranial pressure (ICP) and cerebral blood flow using ultrasonography during inversion table tilt.

METHODS

Optic nerve sheath diameter (ONSD), heart rate (HR), blood pressure, internal carotid artery (ICA) and middle cerebral artery (MCA) blood flow of participants were measured in 3 positions: supine before inversion, during inversion with head down, and supine post-inversion. ONSD was evaluated with ocular ultrasonography and blood flow (ICA and MCA) with Doppler ultrasonography.

RESULTS

The ONSD changed significantly between the supine position, at 3 min of inversion, and after returning to supine position (all P < .001). The post-inversion HR was less than pre-inversion (P = .03) and 3-min inversion HR (P = .003). There were significant changes in ICA and MCA flow caused by inversion, which affected blood flow velocity, resistance, and pulsatility index (all P ≤ .005).

CONCLUSION

Inversion caused significant changes in ICP and blood flow. Thus, increased chance of complications may exist when using inversion as a therapeutic tool or during surgical procedures in patients with previous history of elevated ICP. These results demonstrate that inversion therapy should be used with caution.